Jig saw



W. COPP J IG SAW 3 Sheets-Sheet 1 Filed May 19, 1949 1 d a 5 O o E UWM n n:

wn mm Q E f NN L a in un mQM\ Ng nv INVENTOR WILLIAM CPR @y l lf Nov. 11,1952

w. coPP J IG SAW 3 Sheets-Sheet 2 Filed May 19, 1 949 mvsnron WILLIAM coPP 3J @mf/L ATTORNEY W. COPP Nov. l1, 1.952

J IG SAW Filed May' 19, 1949 3 Sheets-Sheet 3 INVENTOR WILLIAM COPP @y M5 ATTORNEY Patented Nov. 11, 1952 JIG SAW William Copp, Guelph, Ontario, Canada, assignor to` The Callander Foundry & Manufacturing Company Limited, Guelph, Ontario, Canada, a corporation of Ontario Application May 19, 1949, serial No. 94,086

2 Claims.

This invention relates to improvements in jig saws, and has for its general object to increase the operating efliciency of such machines while its principal particular object is to provide in a jig saw novel means for varying the tension in the saw blade while the machine is in operation.

Jig saws which are so constructed that the blade tension may conveniently bevaried during operation are known in the art, and reference is made to W. S. Ocenasek Patent No. 2,165,002, dated July 4, 1939. In such jig saws the upper saw reciprocating mechanism or head comprises a support which is mounted at the end of the usual overarm, and a quill which is translatably mounted on the bracket. In the quill is reciprocatably mounted the spring pressed saw gripping plunger and the quill is connected to the support by a manually operable hand screw whereby the quill may be translated relative to the bracket. v

Known jig saws of the kind described suffer from the disadvantage that to change the tension of the saw blade is a slow and tedious task requiring many turns of the hand screw. Moreover, vibrations in the machin-e combined with the usual tension in the saw blade may cause the hand screw to turn gradually thereby varying the preset tension. Furthermore when the jig saw is used to do what is known in the trade as internal work, the blade must be removed from its chuck, passed through the work, and it must then be readjusted to the proper tension; this requires first taking tension off the blade and nally readjusting it to the same tension, and the use of a hand screw for this purpose causes an undesirable waste of time.

According to the present invention, there is provided in a jig saw a lever which connects the quill and the support and which is manually operable to translate the quill relativeto the support, and there is also provided a separate clamping device to lock the quill against movement'inl tion; 1

Fig.- 2 is a broken-away perspective view of the upper saw reciprocating mechanism head of the jig saw shown in Fig. 1,; j n

y a complete jig saw constructed; in accordance with-this inve'na Fig. 3 is a cross-sectional view taken through the line 3-3 of Fig. 2; y

Fig. 4 is a fragmentary cross-sectional View of the clamping device provided in the aforementionedhead;l

Fig.'5 is an exploded perspective view of the aforesaid clamping device and which is shown adjacent a representative portion of the jig saw head drawn in phantom lines;

Fig. 6 is a broken-away perspective view of a modied jig saw head constructed in accordance with this invention; and

Fig. '7 is a cross-sectional view taken on the line 1-1 of Fig. 6.

Referring now particularly to Fig. l, a jig saw comprises a base I0 at the front of which rises a driving box housing I I that carries at its upper end a work table I2 which is mounted to tilt about a horizontal axis. In the housing I I is provided a well known saw reciprocating mechanism to reciprocate the saw I3 which is connected between the said lower saw reciprocating mechanism and the upper saw reciprocating mechanism which will be subsequently described: power is provided thereto by the V-belt pulley transmission I4 connected to an electrical motor I5. In the housing II may also be provided a suitable air pump which is connected to nozzle I6 by means of tube I'I so as to blow the sawdust away from the immediate vicinity of the saw and of the cut in the workpiece.

Secured to the rear end of the base I0 is an upstanding pillar I8 which blends with an overarm I9. The upper saw reciprocating mechanism which is generally indicated at 20, is secured to the front end of the overarm.

Referring now to Figs. 2, 3, 4, and .5, the upper saw reciprocating mechanism comprises a hollow casing or support 2l secured to the front end of the overarm I9 and in which istranslatably mounted aquill 22. In'a wall of the casing and. parallel to the axis of the quill is provided anl inthe quill and the upper end of which is en gaged by a washer 29 secured to the upper end` of the plungerv by the means of Ya bolt 30.* The spring 21 which is in compression is normally operative `to maintain the plunger resiliently in retracted position and therefore applies tension to the saw blade.- The plunger carries at its"- lower end a saw gripping chuck 3l, which is in registration with the lower saw gripping chuck (not shown), and the blade I3 is secured by and between the chucks. In Fig. 1 there is illustrated a device 32, well known in the art, to guide the saw blade, and also a work presser foot 33. The elevation of the device 32, the presser foot 33 and the nozzle I6 with respect to the work table may be varied by turning screw 34 and moving rod 35 up or down as the case may be.

Through a bearing provided in an enlarged portion at the real` of the support 2l extends a horizontally disposed shaft 36 to one end of which is permanently secured a lever section 31. In the surface of the lever section 31 which is adjacent the casing is provided a longitudinal machined slot 38 in which is slidably mounted afcollar 33 which rotatably `engages the pin 24. l

After the shaft 36 has been assembled in its bearing and the lever section 31 has been propel'- ly tted over the collar 39 inengagement with the pin 24, a ring 46 provided With a-set 'screw 4I is fitted over the free end of the shaft so as to lock it against axial `displacement in the casing or support 2l. Then another lever section 42 having at its free end a handle v43 is suitably connected radially to the shaft 36.

Lever sections 32, 31 and 42 connected'by the shaft 36 together effectively provide -a lever, the

fulcrum of which is the yshaft 36 bearing in the .1

casing 2|, the force applying end of which is the handle 43, and the force applied to the said lever being transmitted to the quill 22 by means of collar 39 and pin 24. The operator of lthe jig saw may thus translate the quill 22 relative to the support 2l by merely shifting the handle 43 in the desired direction.

In another enlarged yportion 44 of the casing 2l is broached an hexagonal bore in which are-slidably mounted Vtwo hexagonal-ly shaped Vcams or studs 45 and 45. The bore provided in the enlarged portion 44 `is so dimensioned and located that it overlaps the main vertical bore in the casing 2l in which is mounted the quill 22, and the studs 45 and 46 are provided with curved chamfers at 45tL and 46a which are of substantially the same radius as the quill 22. Stud-s 45 and45 are bored, threads being tapped in th-e bore of stud 45, -and through 'the studs extends the shouldered shaft 41 of lock lever 48. The threads on the shaft 41 register with the threads provided in stud 45, and thus as the lock lever is'rotated the two studs will be drawn toward-s veach other thereby clamping against the quill at chamfers 45a and 46e. This Idevice therefore provides a clamp to lock the quill against movement in the support, after it has been adjusted to the desired elevation by manual shifting of the handle`43.

At the front end of lever section 31 is a pointer 31a which registers with Ea scale 49 (see Fig. l) to indicate the relative degree of tension in the blade. On the scale appearthe numerals 5, 6, and '1, and above each numeral are some graduations. The scale is so constructed that the tension on a blade is zero if the pointer is set at the numeral corresponding Vto the nominal length of the blade in inches; also, the permissible variations of tension in a blade are indicated by the graduations immediately above each one of the numerals.

Figs. 6 and '1 illustrate a modified jig sawhea'd constructed in accordance with this invention.

Except as hereinafter described the construction of this modified jig saw head is identical to the construction of the one previously described.

Therefore, Wherever applicable, Figs. 6 and 7 have been referenced with the same numerals as the other gures.

In the construction Idisclosed in Figs. 6 and, '1, the free end of the pin 24 is threaded, and it extends through the collar 39' and through the machined'slot 38' of lever section 31. A large locking nut 50 is screwed on the free end of the pin 24' and is 'adapted when tightened to cause frictional engagement between the quill 22, the support 21 and the lever section 31 to thus lock the quill against movement in the support. In

this'constructiom the previously described locking device operated yby the lock lever 43 is not required.

It is thought that the construction and use of the invention will be apparent from the above descriptionof the various parts and their purpose. It is to be understood that the form of the invention herewith shown and described, is to be taken as a preferred example of the same, and that various changes in the shape, size and arrangementof parts may be resorted to, without departing from the spirit of the invention or the scopegof the subjoined claims.

What I 4claim'as'm'y invention is:

l. In a jig saw'of Ythe type in which a saw blade is connected between upper and lower saw reciprocating mechanisms, an upper saw reciprocating mechanism comprising, a support, a quill translatably mounted on said support, a saw grippingplunger reciprocatable in said quill, a, pin secured to the quill transversely thereto and having a free end extending through an elongated slot in the support, a'spring operating between said plunger and said 'quill and normally operative to maintain said plunger resiliently in retracted position, -a shaft Vrotatably mounted on the support and extending transversely of the direction of movement of the quill from one side of the support to theother, a lever including a lever section at one side of the support having one end secured to one end of the shaft and its other end slid-ably and pivotally connected to the free end of thepin and another lever section at the other side of the support having one end secured to the other end of the shaft and its other end providing a handle, the said lever ybeing operable when the handle is shifted to translate the quill relative to its support, and a -cl-amping device which holds the quill firmly again'stfthe support to lock the quill against movement in thesupp'ort.

2. In a jig saw of the type in which a saw blade is connected between upper and lower saw reciprocating mechanisms, an upper saw reciproeating mechanism comprising, a support, a quill translatably mounted on said support, a saw gripping .plunger reciprocatable in said quill, a pin secured to the quill transversely thereto and having a free end extending through an elongated slot in the support, a spring operating between said plunger and said quill and norm-ally operative to maintain said plunger resiliently in retracted positioma shaft rotatably mounted on the support and extending transversely of the direction of movement of the quill .i rom one side of the support to the other, a lever including -a lever section at one side of the support having one end secured to one end of the shaft and its other end slidably and ipivotally connected to the free end of the `pin an-d another lever section at the other handle is shifted to translate the quill relative I 5 to its support, a. scale on said one side of the support, the mst-mentioned lever section having an indicator registering With the scale, lsind a, clamping device which holds the quill firmly against the support to lock the quill against movement in the support.

WILLIAM COPP.

REFERENCES CITED The following references are of record in the le of this patent:

Number 6 UNITED STATES PATENTS Name Date J ac'olb-s June 10, 1902 Highsmith Dec. 24, 1907 Howland Dec. 20, 1910 Bugbee Aug. 29, 19116 McCarter July 12, 1932 Tautz June 26, 1934 Ocenasek July 4, 1939 Brocklebank Nov. 211, l1944 

